# Changelog: Cross-Platform Lifecycle Management

## Version 0.2.4 (Unreleased)

### 🎉 Major Features

#### Cross-Platform Window Lifecycle Management

Added a comprehensive, event-driven window lifecycle management system that works across Windows, macOS, and Linux.

**New Modules:**
- `src/webview/lifecycle.rs` - Core lifecycle manager
- `src/webview/platform/` - Platform-specific implementations
  - `platform/mod.rs` - Platform abstraction trait
  - `platform/windows.rs` - Windows implementation (complete)
  - `platform/macos.rs` - macOS stub (to be implemented)
  - `platform/linux.rs` - Linux stub (to be implemented)

**Key Features:**
- ✅ Event-driven close detection (no more polling!)
- ✅ Guaranteed resource cleanup with `scopeguard`
- ✅ High-performance channels with `flume`
- ✅ Thread-safe lifecycle state management
- ✅ Platform abstraction for easy multi-platform support
- ✅ Better DCC integration (respects host event loop)

### 📦 New Dependencies

#### Production Dependencies

1. **scopeguard v1.2**
   - Purpose: RAII-style resource cleanup
   - Benefits: Guarantees cleanup even on panic, zero-cost abstraction
   - Usage: Defer blocks for cleanup code

2. **flume v0.11**
   - Purpose: High-performance async/sync channels
   - Benefits: Faster than std::sync::mpsc, supports mixed async/sync
   - Usage: Event notification for window close

### 🔧 API Changes

#### WebViewInner Structure

**Added Fields:**
```rust
pub struct WebViewInner {
    // ... existing fields ...
    
    /// Cross-platform lifecycle manager
    pub(crate) lifecycle: Arc<LifecycleManager>,
    
    /// Platform-specific window manager
    pub(crate) platform_manager: Option<Box<dyn PlatformWindowManager>>,
}
```

#### New Public Types

```rust
// Lifecycle states
pub enum LifecycleState {
    Creating,
    Active,
    CloseRequested,
    Destroying,
    Destroyed,
}

// Close reasons
pub enum CloseReason {
    UserRequest,      // User clicked X button
    AppRequest,       // App requested close
    ParentClosed,     // Parent window closed
    SystemShutdown,   // System shutdown
    Error,            // Error occurred
}
```

### 🚀 Performance Improvements

- **Event-driven architecture**: Replaced polling with channel-based notifications
- **Zero-cost abstractions**: `scopeguard` compiles to zero overhead
- **Efficient channels**: `flume` provides better performance than standard library
- **Non-blocking operations**: All event processing is non-blocking

### 🐛 Bug Fixes

- Fixed: Window close not detected in DCC embedded mode
- Fixed: Race condition between window destruction and Rust cleanup
- Fixed: Resource leaks when window closed unexpectedly
- Fixed: Thread safety issues with HWND storage

### 📝 Documentation

**New Documentation:**
- `docs/lifecycle_management.md` - Comprehensive lifecycle guide
- `docs/improvements_summary.md` - Technical summary of improvements
- `docs/CHANGELOG_lifecycle.md` - This changelog

### 🔄 Migration Guide

#### For Existing Users

**Good News:** The changes are backward compatible! Your existing code will continue to work without modifications.

**Optional Enhancements:**

If you want to use the new features:

```python
# Access lifecycle state (future API)
state = view.get_lifecycle_state()

# Request programmatic close (future API)
view.request_close()
```

#### For Contributors

**Windows Platform:**
- Window managers now use `u64` for HWND storage (thread-safe)
- Close detection uses multiple message sources
- Cleanup is guaranteed via `scopeguard`

**Adding New Platforms:**
1. Implement `PlatformWindowManager` trait
2. Add platform-specific close detection
3. Register with `create_platform_manager()`

### 🎯 Future Roadmap

#### Short-term (v0.2.5)
- [ ] Complete macOS implementation
- [ ] Complete Linux implementation
- [ ] Expose lifecycle events to Python API

#### Medium-term (v0.3.0)
- [ ] Custom close confirmation dialogs
- [ ] Graceful shutdown with timeout
- [ ] Lifecycle event callbacks

#### Long-term (v0.4.0)
- [ ] Multi-window lifecycle coordination
- [ ] Advanced cleanup strategies
- [ ] Performance monitoring integration

### 🙏 Acknowledgments

This improvement was inspired by:
- Go's `defer` mechanism
- Rust's RAII patterns
- Modern event-driven architectures
- Community feedback on DCC integration issues

### 📊 Statistics

- **Lines of code added**: ~600
- **New modules**: 5
- **New dependencies**: 2
- **Platforms supported**: 3 (Windows complete, macOS/Linux stubs)
- **Backward compatibility**: 100%

### 🔗 Related Issues

- Fixes: Window close not working in Maya embedded mode
- Fixes: Resource cleanup race conditions
- Improves: Cross-platform support
- Improves: DCC integration reliability

---

**Full Changelog**: [v0.2.3...v0.2.4](https://github.com/loonghao/auroraview/compare/v0.2.3...v0.2.4)

